Auditory Flashcards
What are the 3 collective functions of the outer ear?
1) Gathers sound and focuses on the TM
2) Vibrates the TM
3) Amplifies sound
(Sensation by CN10)
What 3 bones make up the ossicular chain and which is the smallest?
Malleus, Incus, Stapes
Stapes is smallest
What is the role of the ossicles?
Transmit vibrations from tympanic membrane to the oval window
Which muscles alter stiffness of the ossicular chain?
Stapedius, Tensor Tympani
Which nerve innervates middle ear, and which nerve for stapedius, and TT?
Middle Ear - Cn9
Stapedius - Cn7
Tensor Tympani - Cn5
How do the 2 muscles alter stiffness of ossicular chain?
Control Mobility of malleus and stapes
Protecting the inner ear from loud noises
What are the 2 main functions of the vestibular system?
Balance
Spatial Orientation
What is the function of the round window?
1) vibrates with opposite phase to vibrations entering inner ear through oval window
2) Moves fluid in cochlear, so hair cells of BM stimulated and audition occurs
What are the vestibular apparatus?
1) Otolithic Organs: Utricle and Saccule
2) 3 Semi-Circular Canals
What do the Semi-Circular canals detect?
What do otolithic organs detect?
Angular Acceleration
1) Linear acceleration 2) Changes in head position relative to gravity
Location and function of vestibular hair cells?
1) Utricle, Saccule and 3 ampullae at base of S-C Canals
2) Detect changes in motion and position of head by stereocilia transduction
What are the 3 cochlear cavities?
1) Scala Vestibuli (Perilymph)
2) Scala Media (Endolymph)
3) Scala Tympani (Perilymph)
What is the helicotrema?
Meeting of Scala Vestibuli and Scala Media
Which cavity of cochlea houses organ of Corti and what does it sit on?
Scala Media
Basilar Membrane
Describe the Stria Vascularis?
What is the potential of Scala Media
Structure involved in At of K+ into the Scala Media (+80 mV)
